Non shrink grout is a volume-stable cementitious material used in structural base plates, machinery foundations, and grouting applications where gap-free bonding and long-term load transfer are critical requirements.
Table of Contents
- What Is Non Shrink Grout and How Does It Work?
- Key Applications in Mining, Tunneling, and Construction
- Performance Characteristics and Strength Properties
- Selecting and Placing Non Shrink Grout Correctly
- Frequently Asked Questions
- Comparison: Non Shrink Grout vs. Standard Grout
- How AMIX Systems Supports Non Shrink Grout Applications
- Practical Tips for Non Shrink Grout Projects
- Key Takeaways
- Sources & Citations
Article Snapshot
Non shrink grout is a cementitious or epoxy-based material engineered to maintain dimensional stability throughout the curing process, eliminating the voids and gaps caused by conventional grout shrinkage. It delivers tight, load-bearing bonds beneath base plates, machinery pads, and structural anchors in mining, tunneling, and heavy civil construction.
Non Shrink Grout in Context
- Compressive strength reaches 7,000 psi or more for structural applications (Fritz-Pak Corporation, 2025)[1]
- 100% dimensional stability is the primary specification requirement for non-shrink grout products (Tremco Australia, 2025)[2]
- Minimum 3-day damp cure is required to control non-shrink characteristics and maintain strength levels (Quikrete, 2025)[3]
- Rapid strength gain is achieved within 24 hours in accelerated formulations (Amix Systems, 2025)[4]
What Is Non Shrink Grout and How Does It Work?
Non shrink grout is a pre-blended cementitious or epoxy compound specifically formulated to maintain its volume from placement through full cure, ensuring complete and permanent contact between a structural element and its substrate. AMIX Systems, a Canadian manufacturer of automated grout mixing plants and batch systems, works with this category of material across mining, tunneling, and heavy civil construction projects where dimensional stability is non-negotiable.
Standard Portland cement grout loses water during hydration and dries in hot or arid conditions, causing measurable shrinkage that leaves micro-gaps beneath base plates and anchor bolts. Non-shrink formulations counteract this through one of three expansion mechanisms: gas-releasing agents that generate controlled micro-bubbles, expansive cement compounds that swell during hydration, or metallic additives that oxidize and expand to compensate for moisture loss. These mechanisms work during both the plastic (fresh) and hardened stages of curing.
As the American Concrete Institute noted, “A true non-shrink grout will completely and permanently fill a space.” (American Concrete Institute, 2025)[5] That capability matters because any unfilled void beneath a loaded structure concentrates stress at contact edges rather than distributing it evenly across the bearing surface, accelerating fatigue and cracking in the supported element.
Volume-stable grout products must meet ASTM C1107, the standard specification for packaged dry hydraulic cement grout that covers fluid, flowable, and stiff consistencies. The test measures height change from the time of placement to final set, confirming that no net negative volume change occurs. Some high-performance grades also achieve slight positive expansion, ranging up to 0.8% height change per ASTM C827 testing (Quikrete, 2025)[3], which compensates for any later drying shrinkage in service.
Three Primary Formulation Categories
Cementitious non-shrink products rely on Portland cement as the binder and use gas or expansive-additive mechanisms. They suit most structural base plate and equipment foundation applications. Epoxy non-shrink grouts replace the cement binder with a two- or three-component epoxy resin system, delivering superior chemical resistance and higher compressive strength for pump pads, reactor bases, and similar chemically aggressive environments. Magnesium phosphate and other specialty binders form a third category for rapid-set applications where waiting hours for strength development is not practical, such as highway bridge bearing repairs or airport pavement patches.
Choosing among these categories comes down to load magnitude, chemical exposure, placement temperature, and the speed at which the structure must return to service. Each category has distinct mixing requirements that affect the equipment selection for large-volume or continuous-production scenarios.
Key Applications in Mining, Tunneling, and Construction
Non-shrink cement grout serves a broad range of structural applications where gap-free load transfer between components is the defining requirement, spanning surface industrial facilities, underground mines, and major infrastructure tunnels.
In heavy civil and industrial construction, the most common use is beneath steel base plates supporting columns, beams, and machinery frames. The grout fills the space between a precisely levelled plate and a rough concrete foundation, transferring loads uniformly across the full bearing area. Without volume stability, even a hairline gap causes the plate to rock under cyclic loading, eventually cracking the anchor bolts or the concrete below. This scenario is particularly relevant to compressors, turbines, pumps, and other vibrating equipment in petrochemical and power facilities along the Gulf Coast and in Alberta’s oil sands region.
Tunnel boring machine (TBM) operations depend on annular grouting to fill the void between the excavated bore and the precast concrete segment lining. While two-component and bentonite-cement mixes dominate TBM annulus grouting for primary backfill, structural secondary grouting at segment joints and bolt pockets frequently uses non-shrink cementitious formulations to maintain water tightness and structural continuity. Projects such as the Pape North Tunnel for Metrolinx in Toronto and the Montreal Blue Line extension operate in urban environments where settlement tolerance is measured in millimetres, making volume-stable grouting essential.
Mining and Dam Applications
Underground hard-rock mining uses non-shrink grouting for equipment anchor bolts, pump station foundations, and conveyor drive pedestals. Mine shaft collar grouting – where steel headframe steelwork meets the shaft lining – demands materials that maintain tight contact under the dynamic loads transmitted by cage and skip systems. Abandonment and remediation programs for disused shafts also rely on volume-stable fills to prevent surface subsidence in the Appalachian coalfields, Saskatchewan potash belts, and the Sudbury Basin in Ontario.
Dam and hydroelectric grouting programs use dimensionally stable mixes for consolidation grouting of fractured foundations and for contact grouting between concrete dam sections and rock abutments. In British Columbia and Quebec, where hydroelectric infrastructure represents critical provincial assets, long-term dimensional stability of foundation grout directly affects monitoring data from embedded instruments. Any grout shrinkage around embedded piezometers or crack meters skews readings and masks real structural movement.
AGP-Paddle Mixer – The Perfect Storm systems from AMIX provide the controlled batching required to produce consistent non-shrink mixes in high-volume dam and mining applications, ensuring that water-to-cement ratios and admixture dosing remain within specification across extended production runs.
Performance Characteristics and Strength Properties
Non-shrink grout delivers a combination of mechanical properties that standard cement grout cannot match, making it the correct material choice for load-critical connections in industrial and infrastructure projects.
Compressive strength is the most-cited specification parameter. Fritz-Pak Corporation confirms that “many formulations reach strengths of 7,000 psi or more, making them suitable for demanding structural applications. This product helps the grout resist chemical attack, moisture penetration, and freeze-thaw cycles, ensuring your repair withstands environmental challenges and heavy use.” (Fritz-Pak Corporation, 2025)[1] For context, the concrete foundations that non-shrink grout bonds to range from 3,000 to 5,000 psi, meaning the grout itself is the stronger material in the connection.
Early strength gain is equally important on active project sites where delays carry daily cost penalties. Accelerated non-shrink formulations achieve structural strength within 24 hours of placement (Amix Systems, 2025)[4], allowing base plates to be loaded and anchor bolts tensioned the following morning. Standard formulations reach design strength in three to seven days, with a minimum three-day damp cure required to control non-shrink characteristics and maintain strength levels (Quikrete, 2025)[3].
Durability and Long-Term Stability
Tremco Australia describes the long-term requirement clearly: “Non-shrink grouts are essential to ensure the stability and longevity of plant and equipment. A true non-shrink grout will not exhibit shrinkage in either the plastic, or hardened stage of the curing process and will support the plant, or equipment being grouted for the life of that plant, or equipment.” (Tremco Australia, 2025)[2]
Freeze-thaw durability is a significant concern for outdoor applications in Canadian provinces and the northern United States. Entrained air in some non-shrink formulations improves freeze-thaw resistance, but the designer must verify that air entrainment does not compromise compressive strength below the required threshold. Chemical resistance varies considerably between product types: standard cementitious products resist mild acids and sulphates reasonably well, while epoxy-based non-shrink grouts are specified for highly aggressive environments such as acid drainage sumps in mining or chemical process areas.
Bond strength to existing concrete – measured as tensile pull-off strength – determines whether the repair or grouted connection remains monolithic under load reversal or vibration. Proper substrate preparation, including mechanical roughening to ICRI CSP 5 or better and removal of laitance and contamination, is necessary to achieve the rated bond strength of the product. Inadequately prepared surfaces remain the most common cause of grouted connection failure in service.
The Peristaltic Pumps – Handles aggressive, high viscosity, and high density products from AMIX are well-suited to delivering non-shrink mixes to confined placement points such as anchor bolt sleeves and equipment base plate perimeters, where precise metering and the ability to reverse flow for blockage clearance reduce placement risk significantly.
Selecting and Placing Non Shrink Grout Correctly
Correct material selection and disciplined placement procedure together determine whether a non-shrink grout installation achieves its intended performance – the best formulation applied poorly will still fail.
Material selection begins with the project specification, which should reference ASTM C1107 for cementitious products or ASTM C579 for epoxy types. Review the product data sheet for consistency class (fluid, flowable, or stiff) to match the geometry of the space to be filled. Fluid consistency suits base plates with narrow clearances of 25 mm or less where the grout must flow under the plate without vibration. Flowable grades work for wider spaces and are placed by gravity or low-pressure injection. Stiff consistency is hand-packed for small repairs and vertical applications.
Temperature at placement affects both working time and expansion performance. Most cementitious non-shrink products have a specified placement temperature range of 5°C to 35°C. Below 5°C, the gas-generating mechanism is inhibited, reducing the compensating expansion and allowing net shrinkage to occur. Above 35°C, accelerated hydration shortens working time and causes the grout to reach initial set before it has fully flowed beneath the plate. In hot climates such as the UAE or Texas Gulf Coast, pre-cooling the mix water and shading the substrate are standard precautions.
Placement and Curing Procedure
Substrate preparation requires the concrete surface to be clean, sound, and saturated surface dry (SSD) before placement. A fully saturated substrate prevents the dry concrete from absorbing mix water from the fresh grout, which would raise the effective water-to-cement ratio near the bond interface and reduce bond strength. After wetting, remove standing water to avoid diluting the grout mix.
Form construction must be leak-tight because non-shrink grout at fluid consistency will find and exploit any gap. Use non-absorbent form materials or coat wood forms with a release agent. For base plate applications, seal all edges with foam backer rod or hydraulic cement before grouting. Pour from one side only so that air ahead of the advancing grout escapes from the opposite side rather than becoming trapped as a void.
Fritz-Pak Corporation explains the mechanism behind correct placement: “NS-7 compensates for shrinkage in the grout, maintaining dimensional stability as the grout sets. This results in a tight, gap-free bond that seals the repair area and restores the concrete’s structural continuity.” (Fritz-Pak Corporation, 2025)[1] That outcome depends on the placement procedure allowing the expansion mechanism to act without restraint from premature form removal or surface sealing.
Curing begins immediately after the exposed surface stiffens. Wet burlap covered with polyethylene sheeting, or a curing compound applied at the manufacturer’s specified rate, maintains the moisture needed for continued cement hydration and controls early drying shrinkage. Protect the fresh grout from direct sun, wind, and freezing temperatures for at least three days and longer in cold or hot weather extremes.
Your Most Common Questions
What is the difference between non shrink grout and regular cement grout?
Regular cement grout undergoes measurable volume reduction as it hydrates and dries, creating micro-gaps between the grout body and the surrounding structure. This shrinkage – which varies depending on the water-to-cement ratio and ambient conditions such as heat and wind – concentrates load at contact edges rather than distributing it across the full bearing surface. Non shrink grout incorporates expansion-compensating agents – gas-generating additives, expansive cement compounds, or metallic particles – that counteract this shrinkage at both the plastic and hardened stages of curing. The result is a grout body that maintains 100% dimensional stability (Tremco Australia, 2025)[2], filling the grouted space completely and permanently. For structural connections such as column base plates, anchor bolts, and machinery foundations, this distinction directly affects load transfer efficiency, long-term fatigue resistance, and the service life of the connected elements. Standard grout is acceptable for non-structural fill and tile work where minor dimensional change has no structural consequence, but it should never be used for load-bearing grouted connections.
What compressive strength does non shrink grout achieve?
Cementitious non-shrink grout products achieve compressive strengths of 7,000 psi (approximately 48 MPa) or more at 28 days, which exceeds the compressive strength of most structural concrete substrates (Fritz-Pak Corporation, 2025)[1]. Accelerated formulations develop structural strength within 24 hours, making them suitable for projects with tight return-to-service requirements (Amix Systems, 2025)[4]. Epoxy-based non-shrink products exceed cementitious grades, with some achieving compressive strengths above 14,000 psi, though at significantly higher material cost. The appropriate target strength is determined by the design engineer based on the bearing area, applied load, and required factor of safety. For most industrial equipment foundations in mining, petrochemical, and power generation facilities, a minimum 28-day compressive strength of 5,000 psi is specified, meaning standard cementitious non-shrink products provide adequate strength margin. Specify the product grade and consistency class – fluid, flowable, or stiff – to match both the strength requirement and the geometry of the grouted space.
Can non shrink grout be used for underground mining applications?
Non-shrink cementitious grout is widely used in underground mining for equipment foundations, anchor bolt grouting, shaft collar connections, and pump station base plates. The dimensional stability requirement is, if anything, more important underground than at surface because access for remedial work is costly and requires partial equipment removal. In cemented rock fill (CRF) operations, the binder systems used for backfill are not strictly non-shrink products in the ASTM C1107 sense, but volume stability of the fill mass is still a important design parameter for stope stability and ground support. For discrete structural connections underground – such as conveyor drive pedestals and ventilation fan mounts – standard packaged non-shrink grout products are used following the same surface placement procedures, adapted for restricted access and potential water ingress. Automated grout mixing plants from AMIX Systems, including the Colloidal Grout Mixers – Superior performance results, support both CRF production and precision grouting programs in underground hard-rock mining environments across Canada, the United States, and internationally.
How should non shrink grout be mixed for consistent results?
Non shrink grout should be mixed using a mechanical mixer capable of producing a homogeneous blend without incorporating excess air, which would reduce compressive strength. For packaged products, follow the manufacturer’s specified water-to-powder ratio precisely – deviating above the maximum water content reduces strength and inhibits the expansion mechanism. Mix for the full duration specified on the data sheet, at three to five minutes, before checking consistency. On large projects requiring continuous or high-volume production, automated batch plants provide far more consistent results than manual mixing, eliminating human variability in water addition and mixing time. Colloidal mixing technology, which uses high-shear action to disperse cement particles fully before they begin hydrating, produces a more stable and pumpable mix than paddle-only systems. For mining and tunneling projects with sustained production requirements, AMIX automated grout batch systems ensure that water-to-cement ratios, admixture dosing, and mixing duration remain within specification across all batches, protecting both the dimensional stability and compressive strength performance of the final product.
Comparing Non Shrink Grout Options for Structural Applications
Selecting among cementitious, epoxy, and rapid-set non-shrink grout types requires weighing strength, chemical resistance, cost, and placement logistics against the specific demands of each project. The table below summarises the key parameters across the three principal product categories used in mining, tunneling, and civil construction.
| Parameter | Cementitious Non-Shrink | Epoxy Non-Shrink | Rapid-Set Cementitious |
|---|---|---|---|
| Compressive Strength | 5,000-7,000+ psi (Fritz-Pak, 2025)[1] | 14,000+ psi | 3,000-5,000 psi at 4 hours |
| Time to Structural Strength | 24 hrs (accelerated) to 7 days | 24-72 hrs depending on temperature | Under 4 hours |
| Dimensional Stability | Non-shrink per ASTM C1107 | Non-shrink per ASTM C579 | Non-shrink (check product data) |
| Chemical Resistance | Moderate – mild acids and sulphates | High – suitable for aggressive environments | Moderate |
| Relative Material Cost | Low to moderate | High | Moderate |
| Typical Applications | Base plates, anchor bolts, machinery pads | Chemical plant, pump pads, reactor bases | Bridge bearings, pavement repairs |
| Placement Sensitivity | Moderate – temperature and water ratio important | High – requires precise component ratios | High – short working time |
How AMIX Systems Supports Non Shrink Grout Applications
AMIX Systems designs and manufactures automated grout mixing plants and batch systems that support non shrink grout production for mining, tunneling, and heavy civil construction projects worldwide. Our equipment ensures that the precise mixing conditions required for volume-stable grout products are maintained consistently across all production batches, whether the project involves a single equipment pad or a sustained underground foundation grouting program.
Our Colloidal Grout Mixers – Superior performance results use high-shear mixing technology to fully disperse cement particles before hydration begins, producing a denser, more stable mix with improved pumpability compared to conventional paddle systems. This is particularly important for non-shrink formulations, where incomplete particle dispersion compromises both the expansion mechanism and final compressive strength. For projects requiring containerized deployment to remote mining sites or TBM launch shafts, the Typhoon Series – The Perfect Storm provides a compact, self-contained grout plant that travels in a standard shipping container and enters service quickly with minimal site preparation.
Where project duration or budget does not justify capital equipment purchase, our Typhoon AGP Rental – Advanced grout-mixing and pumping systems for cement grouting, jet grouting, soil mixing, and micro-tunnelling applications. Containerized or skid-mounted with automated self-cleaning capabilities. provides access to the same automated batching and self-cleaning mixing technology on a rental basis, suitable for dam repair programs, foundation grouting contracts, and time-limited infrastructure projects.
“We’ve used various grout mixing equipment over the years, but AMIX’s colloidal mixers consistently produce the best quality grout for our tunneling operations. The precision and reliability of their equipment have become essential to our success on infrastructure projects where quality standards are exceptionally strict.” – Operations Director, North American Tunneling Contractor
Our technical team works with project engineers and contractors during equipment selection to match mixer output, pump type, and batching configuration to the specific non-shrink product being used, the placement rate required, and the access constraints of the site. Contact us at sales@amixsystems.com or call +1 (604) 746-0555 to discuss your project requirements.
Practical Tips for Non Shrink Grout Projects
Successful non-shrink grout installation combines material knowledge, careful preparation, and disciplined execution. The following practices apply across base plate grouting, anchor bolt installation, and structural repair applications in mining, tunneling, and civil construction.
Verify product compliance before ordering. Confirm that the specified product meets ASTM C1107 (cementitious) or ASTM C579 (epoxy) and that the product data sheet provides compressive strength data at the required age. Request the most recent test certificates from the manufacturer rather than relying on published typical values, which reflect ideal laboratory conditions rather than field performance.
Control water addition rigorously. The expansion mechanism in most cementitious non-shrink products is calibrated to the manufacturer’s specified water-to-powder ratio. Adding extra water to improve flow dilutes the expansion agent and reduces compressive strength below specification. Use a measured volume of water for each bag and resist the temptation to adjust consistency at the mixer without the manufacturer’s written guidance.
Pre-wet the substrate and anchor bolt sleeves. Saturating the concrete surface and any sleeve or pocket to the saturated surface dry (SSD) condition prevents absorption of mix water from the fresh grout, which causes local stiffening and inhibits flow beneath the base plate. Drain any standing water before placement.
Place from one side continuously. Interrupted pours allow the grout front to stiffen, creating a cold joint that becomes a plane of weakness. Stage your mixing and delivery to maintain a continuous pour rate matched to the volume of the grouted space.
Protect from temperature extremes immediately after placement. Fresh non-shrink grout is vulnerable to both freezing and rapid surface drying. Use insulating blankets in cold weather and wet hessian covered with polyethylene in hot, windy conditions. Maintain protection for a minimum of three days (Quikrete, 2025)[3].
Match pump type to material consistency. Fluid and flowable non-shrink products are placed by gravity or low-pressure peristaltic pump. Stiff consistency materials require hand packing. Using the wrong placement method forces the material past its designed flow range, compromising both the expansion mechanism and the final bond.
For large-scale or continuous production requirements, automated batch mixing plants maintain the consistent water addition, mixing time, and admixture dosing that manual mixing cannot reliably achieve. HDC Slurry Pumps – Heavy duty centrifugal slurry pumps that deliver are suitable for moving mixed grout over longer horizontal distances on large industrial sites, complementing the precision batching that AMIX mixing systems provide.
Key Takeaways
Non shrink grout is the correct material specification for any structural connection where gap-free load transfer and long-term dimensional stability are required. Its combination of volume stability through the curing process, compressive strengths reaching 7,000 psi or more, and durability against freeze-thaw cycling and chemical exposure makes it the standard choice for machinery foundations, base plates, anchor bolts, and precision repair work in mining, tunneling, and heavy civil construction.
Proper material selection – matching product type, consistency class, and temperature rating to the project conditions – combined with disciplined preparation and curing procedure determines whether the installation performs to specification for the service life of the structure. Automated mixing equipment removes the most common source of field variability: inconsistent water addition and mixing duration.
AMIX Systems supplies the automated grout mixing plants, colloidal mixers, and pumping equipment that support consistent non-shrink grout production on projects of any scale. Call us at +1 (604) 746-0555, email sales@amixsystems.com, or visit amixsystems.com/contact to discuss equipment for your next project.
Sources & Citations
- 5 Benefits of NS-7 and Non-Shrink Grout. Fritz-Pak Corporation.
https://fritzpak.com/5-benefits-of-ns-7-and-non-shrink-grout/ - Exploring Non-shrink Cementitious Grouts. Tremco Australia.
https://www.tremco.com.au/buildsmarterblog/concrete/exploring-non-shrink-cementitious-grouts - Non-Shrink General Purpose Grout Data Sheet. Quikrete.
https://www.quikrete.com/pdfs/data_sheet-non-shrink%20general%20purpose%20grout%201585-01.pdf - Non Shrink Grout: Essential Guide for Construction Projects. Amix Systems.
https://amixsystems.com/non-shrink-grout/ - Exploring Non-shrink Cementitious Grouts. American Concrete Institute via Tremco Australia.
https://www.tremco.com.au/buildsmarterblog/concrete/exploring-non-shrink-cementitious-grouts